Effects of salt stress and rhizobial inoculation on growth and nitrogen fixation of three peanut cultivars

Abstract

Increasing soil salinity represents a major constraint for agriculture in arid and semi-arid lands, where mineral nitrogen (N) deficiency is also a frequent characteristic of soils. Biological N fixation by legumes may constitute a sustainable alternative to chemical fertilisation in salinity-affected areas, provided that adapted cultivars and inoculants are available. Here, the performance of three peanut cultivars nodulated with two different rhizobial strains that differ in their salt tolerance was evaluated under moderately saline water irrigation and compared with that of N-fertilised plants. Shoot weight was used as an indicator of yield. Under non-saline conditions, higher yields were obtained using N fertilisation rather than inoculation for all the varieties tested. However, under salt stress, the yield of inoculated plants became comparable to that of N-fertilised plants, with minor differences depending on the peanut cultivar and rhizobial strain. Our results indicate that N fixation might represent an economical, competitive and environmentally friendly choice with respect to mineral N fertilisation for peanut cultivation under moderate saline conditions.

Phylogenetically diverse group of native bacterial symbionts isolated from root nodules of groundnut ( Arachis hypogaea L.) in South Africa

“…The N 2 -fixing ability of groundnut is essential for sustainable yields and economic returns, especially in less developed countries [11]. A common problem encountered by groundnut farmers and growers of other legumes is the presence of low symbiotically efficient native microsymbionts in the soil.…”

Salt dynamics in soil profiles during long-term evaporation under different groundwater conditions

“…Salinity affects physical and chemical characteristics of the soil in the root zone, leading to deteriorated soil structure, reduced infiltration properties and nitrogen fixation, and increased pH, and thus to a reduction in plant yield and quality Rahnama et al 2011;Stefania et al 2012;El-Akhal et al 2013). Once soil salinity reaches the salt threshold, seed germination and vegetative plant growth will be reduced by different ratios (Boscaiu et al 2011;Razzaghi et al 2012).…”

INOCULATION WITH Rhizobial consortium FOR IMPROVING THE GROWTH, YIELD AND QUALITY OF MAIZE UNDER SALT-STRESSED CONDITIONS

“…Indirectly, rhizobia improve plant health by improving the self-defense of plant through induction of systemic resistant (Reddy, 2013) against harmful insects, pathogens, diseases and viruses (Huang and Erickson, 2007). Rhizobia have also been reported to improve the growth and yield of legumes (Ahmad et al, 2012;El-Akhal et al, 2013) and non-legumes (Afzal and Bano, 2008;Bano and Fatima, 2009) under salt stressed conditions. There are extensive reports of rhizobia for enhancement of number of primary roots, root proliferation, and plant growth promotion even under increased level of salinity (Naz et al, 2009;El-Akhal et al, 2013).…”

“…Rhizobia have also been reported to improve the growth and yield of legumes (Ahmad et al, 2012;El-Akhal et al, 2013) and non-legumes (Afzal and Bano, 2008;Bano and Fatima, 2009) under salt stressed conditions. There are extensive reports of rhizobia for enhancement of number of primary roots, root proliferation, and plant growth promotion even under increased level of salinity (Naz et al, 2009;El-Akhal et al, 2013). Further, it has been demonstrated that coinoculation or multi-strain consortium of rhizobia with other PGPR or mycorrhizae gave better improvement than their alone inoculation under normal as well as salt stressed conditions (Yu et al, 2007;Afzal and Bano, 2008;Bano and Fatima, 2009).…”